Splined shafts are well known and are often used to transfer torque from one shaft to another. A splined shaft comprises a shaft, and a set of splines or teeth spaced around an outer circumference of the shaft and in use is arranged such that its teeth are securely interlocked with the teeth of another object. The splined shaft is rotated and this rotational force is transferred to the toothed object through the engagement of the teeth.
In some instances it is advantageous for the teeth to be formed as part of the shaft, and for the teeth to be overmoulded with a continuous outer layer, typically of plastic, which can serve to provide a variety of advantages over an equivalent shaft which does not comprise an overmoulding. For example, an overmoulding can be made of a softer, more elastic, material relative to the harder material of the shaft and underlying teeth which can result in reduced noise from the transfer of torque through the splined portions. Alternatively a hard over moulding material may be used over a steel shaft and teeth and through the molding process the precise shape and size of the finished splined shaft can more readily be controlled compared with the machined shaft and teeth.